Apparatus for forming system components of extruded hollow chamber profiles

ABSTRACT

This disclosure teaches a structural system with extruded plastic members having hollow (preferably rectangular) profiles with their ends open. Connecting plugs are provided for engagement into the open ends for attachment to the members. Embossed toothing at the open ends interfacing the plugs and the members secure their attachment. Embossing devices are used to emboss the toothing on the internal and external surfaces.

United States Patent [191 Duepree 451 Aug. 21, 1973 APPARATUS FORFORMING SYSTEM COMPONENTS OF EXTRUDED HOLLOW CHAMBER PROFILES [76]Inventor: Hans-Werner Duepree,Osnabrueker Landstrasse 154, Avenwedde,Germany [22] Filed: Sept. 3, 1971 [21] Appl. No.: 177,666

[52] US. Cl. 425/392, 264/322 [51] Int. Cl. B29c 23/00 [58] Field ofSearch 425/384, 385, 393;

[56] References Cited UNITED STATES PATENTS 1,352,418 9/1920 Boyer264/320 X 3,130,412 4/1964 Fox et a1.....1 425/385 X 3,349,599 10/1967Ullmann et a1. 72/393 3,384,695 5/1968 Murray 264/322 X 3 ,425,093 2/1969 Ansette 3,478,144 11/1969 Sato 425/385 X FOREIGN PATENTS ORAPPLICATIONS 566,760 4/1958 Belgium 425/385 Primary ExaminerR. SpencerAnnear Attorney-Erich M. H. Radde [57] ABSTRACT This disclosure teachesa structural system with extruded plastic members having hollow(preferably rectangular) profiles with their ends open. Connecting plugsare provided for engagement into the open ends for attachment to themembers. Embossed toothing at the open ends interfacing the plugs andthe members secure their attachment. Embossing devices are used toemboss the toothing on the internal and external surfaces.

2 Claims, 16 Drawing Figures Patented Aug. 21, 1973 3,753,640

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wk MW APPARATUS FOR FOA NG SYSTEM COMPONENTS OF EXTRUDED HOLLOW CHAMBERPROFILES BACKGROUND OF THE INVENTION 1. Field of the Invention Thepresent invention relates to the processing of plastic materials and themanufacture of plastic articles and more particularly to an arrangementand a process of producing plastic system components in the form ofhollow-chamber profiles which are produced from plastic by the extrusionprocess.

2. Description of the Prior Art Hollow-chamber or box profiles ofplastic materials produced by the extrusion process are of preferred useas system components for the manufacture of frames, boxes, cabinets, andthe like due to the advantages in their manufacture. However, up to nowconsiderable difficulties have been encountered with respect to a properconnection of the corners of hollow-chamber profiles made in this mannerbecause in the case of these profiles it is not possible during theirmanufacture to produce recesses or protrusions which would pennit asimple and rapid connection of the comers; for the extrusion processpermits the production of shapes extending in longitudinal directiononly. Therefore, in order to achieve proper corner connections inextruded hollow-chamber profiles, fins mutually engaging each other areinserted into the hollow chambers of the profile after providing a mitercut therein which, however, leaves the outer wall standing, and theprofile is then bent together at the apex of the miter.

In accordance with another known arrangement, the extrudedhollow-chamber profiles, cut to length, are connected to each other byplugs. The plugs are designed as angle members and are preferably ofextruded plastic material. They are then provided in subsequentoperations with special appendices of stamped or punched metal sheets.These metal sheets form, in the region of the plugs, protruding barbswhich, after assembling the plug connection, rest against the innerwalls of the hollow chambers and are anchored therein. Aside from thecostly additional machining or finishing of the plugs, such connectionsare not very durable or firm. Of course, it has also been proposed toeffect such connections by means of corner plugs in which, after joiningthe corner plugs and hollow chamber profiles, a transverse bore hole wasproduced into which a pin is inserted. Such connections, to be sure,hold firmly together, but in order to obtain a connection which isparticularly resistant to twisting, the bore holes and transverse pinshad to be arranged in a special manner, resulting in complicationsduring manfuacture. It usually was necessary to efiect additionalattachment by means of an adhesive. As is known, bonding of plastics bymeans of an adhesive is not possible in all cases since there arescarcely any adhesives which adhere equally firmly, for instance, on theone hand to polyvinyl chloride and on the other hand to polystyrene;furthermore, such plastic adhesives are extremely expensive and causesubstantial complications in the manufacturing process. Heretofore, allknown or suggested connections of the comers of extruded plasticprofiles up to the present time require considerable subsequentmachining, additional measures and materials, as well as expensivemanual labor it being not possible in many cases to obtain a connectionwhich is easily produced but nevertheless firm, dependable, andparticularly resistant to twisting.

SUMMARY OF THE INVENTION It is one object of the present invention toprovide a simple and highly efiective method of firmly andsatisfactorily joining extruded plastic articles at their end so as toform corners.

Another object of the present invention is to provide plastic parts orarticles which are firmly joined and connected to form comers.

Other objects of the present invention and advantageous features thereofwill become apparent as the description proceeds.

In principle the present invention of providing system components ofextruded hollow chamber profiles of plastic material which can beconnected to form corners by means of connecting plugs, is characterizedby the feature that profile sections are provided with a toothing in theregion of their ends on an inner surface of at least one chamber. Saidtoothing is preferably embossed therein. The embossed toothings can alsobe arranged at two opposite inner surfaces of at least one chamber. Thehollow-chamber profiles can also be composed of two open profile partsassembled by means of a continuous hook-connection, the hooks engagingbehind each other on longitudinal ribs. The plugs preferably have anopen U-shaped profile and are provided with the toothing on the outerside of their base. The plugs in the form of an open U-shaped profilecan also be provided with the toothing on the outer side of the arms ofsaid profile. The plug walls are preferably of smaller thickness in theregion of the toothing as a whole or towards its edges. The walls of thechamber profiles can advantageously be made of smaller thickness in theregion of the toothing towards the edges.

One method producing hollow chamber profiles in accordance with thepresent invention is characterized by the feature that one or moreembossing plugs are introduced endwise into one or more chambers of thehollow profile and are pressed on the softened corresponding innersurfaces in order to emboss thereon the toothing.

Another variant of the method of producing hollow chamber profiles ischaracterized by the feature that one or more embossing jaws which arearranged opposite each other and between spreading wedges aredisplaceably arranged, are introduced at the end into one or morechambers of the hollow profile and are pressed in while softening theirinner surfaces, by displacing the spreading wedges so as to emboss thetoothing. When pressing the embossing tools from the inside of thehollow chamber profile, the latter is stabilized by jaws applied inopposing direction, shaped, and, if required, cooled.

One method of producing hollow chamber profiles from open profiled barsis characterized by the feature that by means of an embossing wheelwhich acts against the inside of the profiled bars or by means of anembossing stamp which can be raised or lowered, they are provided withthe toothing while softening the surface to be shaped.

As is evident toothing with a plurality of teeth lying one behind theother on connecting plugs and system component gives a connection whichis extremely easy to produce in assembling, but which is neverthelessvery strong, stable, and permanent. In this connection many differentforms of teeth can be employed; a barbshaped toothing is particularlyadvantageous. To use such a connection for extruded hollow chamberprofiles was not possible heretofore because said special moldingprocess does not permit production of indentations extendingtransversely to the injection nozzle. In contrast thereto and inaccordance with the present invention, such indentations arrangedtransversely to the direction of extrusion are embossed subsequently bya special molding tool after the hollow profiles have been cut to thedesired length from their ends, whereby the inner surfaces are softened.Or, according to another embodiment of the present invention the hollowchamber profile is so divided up in length that it is composed of twohalves. In this case the toothing can be formed by means of an embossingwheel or a moving embossing stamp during the continuous course ofmanufacture, i.e., directly after the extruded profile has left theinjection nozzle or the calibrating nozzle and is still somewhatplastically deformable. The embossing wheel has its shaft supported infixed position in a frame and rolls in contact therewith, while theextruded profile is moved over its surface. Thereby, the embossing stampmoves up and down on said profile and moves along with the extrudedprofile during the embossing process. Of course, the embossing of theopen hollow chamber profiles can also be effected at a later time,provided care is taken that the inner surfaces are softened forembossing.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects,advantages, and features of the present invention will be more fullyunderstood in connection with the following description of certainpreferred embodiments thereof, taken in conjunction with theaccompanying drawings without, however, being limited thereto. In saiddrawings FIG. 1 is a perspective view of two types of comer connectionsshown in the form of an exploded drawing;

FIG. 2 is a longitudinal section through a first embodiment of anembossing tool;

FIG. 3 is a longitudinal secton through another embodiment of anembossing tool;

FIGS. 4a-4d are perspective views of different embodiments of thetoothings in a hollow chamber profile and on the plug correspondingthereto;

FIG. 5 is a cross section through a special embodiment of an extrudedhollow chamber profile;

FIG. 6 is a cross section through a hollow chamber profile assembledfrom two halves;

FIG. 7 is a cross section through a hollow chamber profile assembledfrom two halves in accordance with another embodiment;

FIG. 8 is a perspective view of one half, corresponding to FIGS. 6 or 7,of the hollow chamber profile;

FIG. 9 is a longitudinal section through a toothing device for a profilein accordance with FIGS. 6 to 8;

FIG. 10 is a longitudinal section through a toothing devicecorresponding to FIG. 9 in another embodiment;

FIGS. 1 l, 1 1b, and 1 1c show different forms of teeth.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The perspective view of FIG. 1shows the manner in which the hollow chamber profiles as systemcomponents are connected with each other by meansof a plug connection,either by means of a special part connecting two hollow chamber profilesat their ends to form a corner. Said part consists of plugs arranged atan angle to each other. Or the plugs can form an integral part of one ofthe system components produced, for instance, by injection molding.According to FIG. I there are provided on comer connecting part 1 or onthe system component 1a plugs 2 arranged at a right angle to each otheror to system component 1a. Said plugs 2 have toothed outer surfaces 3the teeth being constructed as hooks. The box profiles 4 are extrudedprofiles with flat reactangular cross section which have on their insideseveral transverse ribs or webs S which stiffen and strengthen the boxprofile, and particularly the extended outer surfaces thereof. Onextruding said box profiles 4 it is not possible to provide the innersurfaces of the individual chambers of the profiles 4 with toothingsinto which the plugs 2 with their toothings can engage, since suchtoothings have to extend transversely to the directon of extrusion.

Therefore, after the continuously extruded box or hollow chamberprofiles 4 have been cut to the desired length, they are provided bymeans of a special embossing tool such as shown in FIGS. 2 or 3, withthe barb indentation. g

The embossing tool of FIG. 2 consists of an embossing plug 6 ofrectangular cross section, the lengths of its sides being smaller thanthe lengths of the sides of the inner cross section of a chamber of thehollow chamber profile 4. The embossing plug 6 is provided on one of itssurfaces with an embossing toothing 7 which is coated with a releaseagent, for instance, with silicone or polytetrafluoroethylene, so as toprevent its adherence to the softened plastic after embossing. Theembossing plug 6 is provided in its interior with a heating means 8 anda temperature detector. The embossing plug 6 is attached to a guide 9which introduces it for embossing into the chamber 4. Plug 6 is thenpressed against the wall to be embossed. After embossing, it is liftedoff and is withdrawn, as shown by the arrows indicated on guide 9. Onguide 9 there is furthermore displaceably arranged jaw 10 which ismovable toward and from the direction of movement of plug 6. Said jaw 10rests during embossing and softening of the chamber wall by heatingmeans 8 on the surface opposed to the surface of said wall which will beembossed and, thereby, stabilizes and strengthens it when the heatedembossing tool 6 acts on said surface. Stabilizing and strengthening jaw10 can be cooled, if required.

The use of the stabilizing and strengthening jaw 10 produces anadditional advantage when a toothing is embossed by means of theembossing tool 6 on the surface of one of the wall surfaces of the innerribs 5 (FIG. 1) of the chamber profile 4. As is known, hollow chamberprofiles, after extrusion, are brought to the proper dimensions by meansof a calibrating nozzle. Thereby, however, it is not possible toprecisely mold the ribs between the chambers. These ribs therefore areusually not of exact measurements; they frequently are bent, arched, orotherwise deformed. Such deformations are disadvantageous when the plugconnections are introduced at the end. By the provision of stabilizingand strengthening jaw 10 it is possible to properly emboss the wall ofan inner rib by placing the stabilizing and strengthening jaw 10 placedagainst the other side of said wall 5 opposed to the embossing plug 6,thus aligning the molding the rib 5 exactly to the desired dimensions,at least within the area where plug connection is effected, therebyeliminating any deformation. To achieve this result it is only necessaryto suitably control the temperature so that during embossing the rib hassoftened to such an extent that it can be molded under the pressureexerted by the embossing tool 6 and the stabilizing and strengtheningjaw 16 It has also proven of advantage to somewhat increase thethickness of the wall of the hollow chamber profile 4 which is to beprovided with the embossing, whereby, however, the thickness of the wallmaterial preferably decreases towards the lateral longitudinal edges (asindicated in the cross sectional view of FIG. 5). Then the embossingtool 6 is merely of a width which corresponds to the thicker part of thewall. In this way two advantages are achieved. On the one hand, onembossing, the softened material which has been displaced at the apicesof the teeth can give way towards the sides. On the other hand, due tothe material being weakened in the vicinity of the longitudinal lateraledges, the result is achieved that this part of the wall has a greaterelasticity which favors and facilitates introduction and locking of thetoothing of the connecting plugs.

In accordance with another embodiment of the present invention as shownin FIG. 3, an embossing tool for embossing of toothings on oppositeinner walls of the hollow chamber profile consists essentially of twoembossing jaws 11 which are positioned opposite each other and the outersurfaces of which are shaped as hook toothing 12 to be embossed. Betweenthese embossing jaws 11 there are displaceably arranged spreading wedges13. These wedges 13 are constructed in the embodiment shown in FIG. 3 sothat the opposite facing surfaces of the embossing jaws 11 have aplurality of inclined surfaces 14 arranged one behind the other andextending towards each other. Correspondingly obliquely inclinedsurfaces 15 on the spreading wedge 13 cooperate with the said obliquesurfaces or wedge surfaces 14 of the embossing jaws 11 in such a mannerthat upon displacement of said embossing jaws l1 and said spreadingwedges 13 with respect to each other in the direction indicated by thearrows, the embossing jaws 11 are pressed against the walls of thehollow chamber profile 4. The inner surfaces of said walls are softenedfor embossing. Softening can also be effected by heating the embossingjaws 11, before introducing them into the hollow chamber profile 4, to apredetermined temperature at which, with due consideration of theinterim cooling effect, softening of said inner surfaces sufficient forembossing takes place. When using plastics which, due to their specificcomposition, have a wide temperature range within which they soften, thehollow chamber profile 4 as a whole can also be heated to the softeningtemperature prior to embossing. Another possible manner of softeningconsists in increasing the temperature to the softening temperature byexposure to high frequency current at the boundary surfaces betweenembossing stamp and plastic profile. It is advisable, during embossingand thus as long as the plastic profile is softened, to apply to it fromthe outside pressing jaws 10 which cause the outer shape of the profilesto be retained and which are cooled, if required.

Various possibilities of providing toothing in the hollow chamberprofile are shown in FIG. 4, the correlation of the plugs to thetoothings to form the hollow chambers being illustrated in partialperspective view. In an outer chamber a toothing is arranged in the ho]-low chamber profile on the inside of an outer wall at its bottom (FIG.44). Two different types of plug are shown for such a toothing, namely alower plug embodiment in which the plug has a U-shaped profile and isprovided with the toothing on the outside of the base surface. Thistoothing is bevelled towards the lateral longitudinal edges so that thewall of the plug is somewhat thinner in this region. At this place thematerial displaced in the hollow chamber upon embossing is taken up. Inaddition thereto the result is achieved that by so weakening the wall ofthe plug, a certain elasticity is created permitting simpler assembly ofthe plug and hollow chamber.

FIG. 40 shows a U-shaped plug in which the toothing extends from edge toedge.

FIG. 4 also shows a central chamber which is provided with a toothing onone of its side walls, i.e., on the inner surface of a rib.Corresponding to this side wall toothing FIG. 4d shows a plug ofU-shaped cross section which bears the toothing on the outer surface ofone of its arms.

A particularly advantageous and useful embodiment of the presentinvention consists in the feature that a complete hollow chamber profileis not produced directly upon the extrusion, but that first partial, forinstance, half profiles are extruded which are subsequently assembledtogether to form a hollow chamber or box profile. FIGS. 6 to 8illustrate such profile shapes. In FIG. 5 the hollow chamber profile 4is composed of two open partial profiles. The center ribs are designedin the form of hook ribs 16 which engage behind each other and thenarrow sides can be provided with an interengaging stepped toothing I7in order to avoid formation of any substantial gap. When the hollowchamber profile of FIG. 6 is composed of two nonidentical open profiles,it is advisable to arrange the stepped toothing 17 in such a manner thatit lies at a longitudinal edge. It can easily be seen that the two openprofile parts are assembled in a simple and rapid manner to form aclosed hollow chamber profile by placing said parts upon each other andpressing them together so that the barbs of the opposing hook ribs 16engage each other and hold the profile firmly and securely together. Thestepped profiles 17 on the sides also engage each other.

While a hollow chamber profile assembled in accordance with FIG. 6 fromtwo open profiles requires two different extrusion forms, a hollowchamber profile composed of two open profiles in accordance with FIG. 7can be extruded from a single extrusion nozzle; The interengaging hookribs 16 are in identical position in the embodiment of FIG. 6, i.e., thehooks of the upper profile part point towards the left and the hooks ofthe lower profile part point towards the right. Displacement of the twoprofile parts and thus disengagement and loosening of the interengaginghooks 16 is prevented by providing a corresponding opposite facing steps17 in the narrow side walls of the profile parts. Displacement can alsobe prevented by providing additional corresponding ribs 18 which fonn alongitudinal wall of the hollow chamber profile and engage each other.Of course, it is possible, depending on the re-' spective shape anddimension of the hollow chamber profile, to provide a large number ofhook ribs 16 and interengaging ribs 18 within the profile. It is evidentthat the profile shape of FIG. 7 consists of two identical profile partswhich, however, are arranged opposite each other as mirror images.

Due to the simple division of a hollow chamber profile into two openextruded profile parts, it is readily possible in accordance with thepresent invention to continuously provide in said open profile partsduring the course of their manufacture a barb toothing 7, as illustratedin particular in FIG. 8. Of course, thereby the desired longitudinalextention of the system components must be taken into consideration sothat opposite barbed shapes are present at all times at each end of theprofile length. The extrusion of the profile parts can be controlled inthe manner that, upon leaving the extrusion die or the calibratingdevice, they are still so soft that the barbed shape can readily beembossed by means of a suitable embossing tool. It is also possible toheat the embossing tool in a suitable manner so that the surface to beembossed will be softened during embossing. it is also advisable tosupport the profile parts during embossing from the outside so that theyretain their original shape. For continuously embossing the extrudedopen profile parts, there can be used an embossing wheel 19, such asshown in FIG. 9, which is provided on its cylindrical surface withbarbed toothing 20. This embossing wheel, upon the advance of theextruded open profile part, rolls or hobs on the corresponding innersurfaces of said profile part and provides it thereby with the desiredembossing. The circumference of the wheel and the embossing toothing onits cylindrical surface are so adapted to each other that the requiredbarbed toothing is embossed each time at the ends of the longitudinalextension of the profile parts as desired in each case.

Another possibility of molding the barbed toothing on the extruded openprofile is shown in FIG. 10. Here the barbed profile is pressed by meansof an embossing stamp 21 against the inner surface of the open profilepart and travels along with the extruded profile part with the speed ofadvance during the embossing process. After embossing, the stamp 21 iswithdrawn and is returned to its starting position so that embossing canbe repeated. The directions of movement of the stamp are indicated byarrows. Of course, two such embossing stamps can also be usedalternately in order to emboss toothings which are opposed to eachother.

In FIG. 11 there are shown various shapes of tooth profiles which can beused for the purpose of the present invention: FIG. 11a illustrates abarbed profile which can easily be placed together and assures excellenthold and firmness, but is not detachable. FIG. 1 1b illustrates a simpletooth profile with teeth having equilateral flanks. FIG. 11c illustratesan undulated profile. The last two profiles, suitably shaped, can bedetached.

From the above description it can be noted that it is possible to applyto extruded profiles the particularly advantageous embodiment ofconnecting by means of barbed toothings hollow chamber profiles and plugprofiles. In particular such connections can also be effected by thevery advantageous and suitable step of dividing the hollow chamberprofile into two open halves into which the barbed toothing can beembossed or molded already during the continuous extrusion of saidhalves.

I claim:

1. A device for embossing toothing onto an inner wall of an extrudedplastic member having a hollow profile with an open end, the devicecomprising in combination:

spreading wedges insertable into the open end in contact with the wall,

means for heating the inner wall to soften it,

means for pressing the spreading wedges against the softened inner wallto emboss the toothing thereon, lifting means for lifting the spreadingwedges from the inner wall,

means for removing the spreading wedges from the open end,

stabilizing means provided at the outside of the wall to be embossed,said stabilizing means movable toward and from the wall to be embossedand on contacting said wall reenforcing same to prevent bending thereofon embossing.

2. Thedevice of claim 1, in which the stabilizing means are providedwith cooling means.

I! 1' i I UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent:No. 3,753,640 Dated August 21, 1973 Inventor s) lt'is certified thaterror appears in th-above-ddentified patent and that said Letters Patentare hereby corrected as shown below:

Claim 1 should read as follows:

1. A device for embossing toothing onto at least one inner wall of anextruded plastic member having a hollow profile with an open end, thedevice comprising in combination:

a spreadable embossing tool insertable into-the open end of said memberin contact with said one wall,

means for inserting said embossing tool into said open end,

means for heating said one wall to soften it,

wedge means for pressing said embossing tool against the softened innerwall to emboss the toothing thereon,

3 lifting means for lifting said embossing tool from the inner wall,

means for removing said embossing tool from the open end of saidmember,and

FORM PC4050 (10-69) uscowwoc uosve-poo' Page 2 UNITED STATES PATENTOFFICE CERTIFICATE OF CORRECTION Patent No- 3,753,640 Dated Auggst 21,1973 Inventor(s) HANS-WERNER DUEPREE It is certified that error appearsin the above-identified patent and that said Letters Patent are herebycorrected as shown below:

stabilizing means provided at the outside of the wall to be embossed,said stabilizing means being movable toward and from the Wall to beembossed and on contacting said wall reenforcing same to prevent bendingthereof on embossing.

Signed and sealed this 21st day of May 1974.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. I C. MARSHALL DANN Attesting Officer Commissionerof Patents FORM P1050 (10-69) UscoMM-QC 503754559

1. A device for embossing toothing onto an inner wall of an extrudedplastic member having a hollow profile with an open end, the devicecomprising in combination: spreading wedges insertable into the open endin contact with the wall, means for heating the inner wall to soften it,means for pressing the spreading wedges against the softened inner wallto emboss the toothing thereon, lifting means for lifting the spreadingwedges from the inner wall, means for removing the spreading wedges fromthe open end, stabilizing means provided at the outside of the wall tobe embossed, said stabilizing means movable toward and from the wall tobe embossed and on contacting said wall reenforcing same to preventbending thereof on embossing.
 2. The device of claim 1, in which thestabilizing means are provided with cooling means.